Preliminary evaluation of the potential of 99mTc carbonyl–DTPA–Rituximab as a tracer for sentinel lymph node detection

•Proposal of 99mTc-labeled Rituximab as a sentinel lymph node (SLN) tracer.•99mTc carbonyl DTPA–Rituximab obtained in good radiochemical purity.•In vitro cell binding studies confirmed presence of higher CD20 receptor density on malignant cells.•Tested in Wistar rat using footpad model (popliteal node uptake).•Significant SLN uptake and retention of 99mTc carbonyl labeled Rituximab in animal model.

Preliminary work with 99mTc carbonyl–DTPA–Rituximab was attempted to test its feasibility as a sentinel lymph node (SLN) tracer for patients with breast cancer. 99mTc labeling of DTPA–Rituximab conjugate was carried out via 99mTc carbonyl synthon which exhibited >95% radiochemical purity and good in vitro stability. In vitro studies of 99mTc carbonyl–DTPA–Rituximab in normal and malignant B cells showed higher binding in malignant cells. In vivo distribution of 99mTc carbonyl–DTPA–Rituximab in Wistar rat footpad model indicated good retention by B-cells present in the sentinel lymph node.